Carburetor



June 14, 1932. c. F. JOHNSON CARBURETOR Filed May 24, 1929 5 m I i W j. 5M yf ,f 16 m Patented June 14, 1932 PATENT GFFCE CHESTER F. JOHNSON, OF DETROIT, MICHIGAN CARBURETOR Application. filed May 24,

rlhis invention relates to a carburetor for internal combustion engines and has special reference to improvements in carburetors of the air valve type incorporating stabilizer wells or dashpots for the air valve.

lt is an object of this invention to improve on existing carburetor-s of this General type wherein it has been found that the fuel and air mixture with a single fuel delivery nozzle increased in richness to a necessary extent under conditions of maximum power or wide open throttle at slow speed. @ne method of accomplishing the object of this invention is to provide an improved and amplified auxiliary nozzle discharging into the auxiliary air stream.

The disclosed embodiment of this invention also resulted in other advantages aside from the desired mixture quality, namely, the provision of a much richer mixture for starting whenever a choke is used; that the quality of the mixture under low speed full load conditions can be more closely regulated without in any way detracting from the desired quality of the mixture at higher speeds, and the improved structure permits a greater operating clearance in the stabilizer well, thus obviating troubles due to sticking or misalignment of the parts therein, as well as closing the well to the atmosphere, preventing the collection of road dirt around the stabilizer rod and plate.

Other and further important objects of this invention will be apparent from the disclosures in the specification and the accompanying drawing.

This invention (in a preferred form) is illustrated in the drawing and hereinafter more fully described.

On the drawing:

Figure 1 is a section through a carburetor embodying the features of this invention.

Figure 2 is an enlarged fragmentary section on the line lI-II of Figure 1.

Figure 3 is an enlarged fragmentary section on the line Ill-Ill of Figure 1.

As shown on the drawing:

A carburetor body comprises a mixing chamber 11 and a lateral extension 12 having port 13 adapted to be controlled by an 1929. semi No.v 365,701.

auxiliary air valve member 14 which is pivoted at 15 and adapted to be yieldingly closed by a spring 16 the lower end of which may be raised by a movable sprino' seat 17 formed on a plunger 18 which may be externally adjusted by means of a lever 19 whereby the opening of the valve may be retarded or restricted to enrich the mixture. A conventional butterliy throttle valve is indicated at Q0 at the top of the mixing chamber.

The body 10 carries a slotted boss 21 at the bottom of the mixing chamber which boss is internally formed as a diverging nozzle or choke tube and has an external sleeve Q2 slipped thereover to form in effect a primary venturi, the slots 23 in the boss serving to drain accumulations of liquid fuel in the body back to the throat 24 of the choke tube where such fuel will be picked up by the air flowing therethrough. 70

A float bowl cover 25 is detachably connected to the carburetor body vand has attached thereto a fuel chamber 2G. For the sake of simplicity the usual float controlled fuel admission valve has been omitted from the drawing it being understood that the fuel is maintained at a constant level in the chamber as indicated by the reference number 27. The cover 25 is provided with a cup shaped portion 28 surrounding the lower end or throat 24 of the Venturi or choke tube; and with a control nozzle 29 extending slightly into the throat 24 of the venturi. A passage 30 leads to the nozzle from a needle valve chamber 31 a needle valve 32 therein controlling the effective area of a passage plug 33 communicating with the top of a. vertical passage 34 extending considerably below the fuel level 27 in the chamberl 26.

A central well 35 is formed in a depending boss, and has a passage 36 connecting the well 35 with the passage 34. lVhen first the motor cranked over, the suction existing in the chamber 12 is transferred by means of the tube 37 to the well 35. This suction. is then transferred to passage 34 by way of the passage 36, causing the liquid fuel to l'low through passage 36 into well 35, displacing the air therein until the liquid fuel reaches the bottom end of tube 37. In this manner the Well is lled, and thereafter Will s0 remain regardless of whether the engine is running or not; also regardless of the amount of fuel in the float bowl.

The air valve 14 carries an eye 38 to which is connected a rod 39 leading through the tube 37 and carrying a loosely fitting stabilizer plate submerged in the fluid in the well. This plate serves to prevent fluttering of the air valve due to periodic variations in suction in the carburetor. The rod has a substantial clearance inv the tube 37 so that the angular displacement, due to the swinging movement of the air valve, does not produce binding. As shown, the tube 37 is held at its upper end in an aperture in the body 10 while its lower end is centered in the well by discs and packing 41. y

In the operation of the carburetor of this invention at low speeds of the engine without `load, the air entering the throat of the choke tube 21 around the nozzle .29 picks up fuel therefrom and is over-rich to such an extent that ithas to be qualified by means of some amount of air entering past the air valve 14, the amount of which is regulated by means of the idle adjusting screw 19a. Thus the air valve is always floating some distance from its seat even at the slowest idling speeds,and when manually held to its seat by means of the choke control produces a very rich mixture, such as may be required for cold starting'. The amount of suction in the chamber 12 is not sufficient to cause a ow of fuel to be discharged through the tube 37 .either throughout the lower throttle range or at low open throttle speed under heavy load and consequently low suction. But at a` somewhat higher speed the suction gradually increases to such an extent that fuel will be delivered therefrom in increasing quantities as the speed increases. Vith this arrangement an economical or lean mixture can be maintained under conditions of low and medium engine speed, while the auxiliary nozzle comes into action when the carburetor suction increases to an extent sufficient to lift fuel through the tube 37.

It will thus be seen that I have provided an improved and simplified carburetor capable of producing a lean and economical mixture for normal operating -conditions while auto- 1 the kpatent granted hereon, otherwise than .necessitated by the prior art.

I claim as myinvention: 1. A carburetor ycomprising a mixing chamber, a choke tube opening thereinto, a fuel nozzle discharging into said choke tube,

a fuel reservoir for supplying fuel to the nozzle, a stabilizer well supplied with fuel from said reservoir, an air valve for supplying additional air to said mixing chamber, a stabilizer plate in said well and connected to said air valve to be moved thereby, and a tube connecting said well and said mixing chamber and surrounding the connection between the air valve and the stabilizer plate, said tube being adapted to supply fuel to said mixing chamber from said well under all but low depressions.

2. A carburetor comprising a mixing chamber, a choke tube opening thereinto, a fuel nozzle discharging into said choke tube, a fuel reservoir for supplying fuel to the nozzle, a needle valve Vadapted to meter the supply of fuel to said nozzle, a stabilizer well supplied with fuel from said reservoir, an air valve for supplying additional air to said mixing chamber, a stabilizer plate in said well and connected to said air valvev to be moved thereby, and a tube vconnecting said well and said mixing chamber and surrounding the connection between the air valve and the stabilizer plate, said tube being adapted to supply fuel to said mixing chamber from said well under conditions as described.

v3. A carburetor comprising a mixing chamber, means for discharging fuel into the mixing chamber, a fuel reservoir for supplying fuel to said means, an air valve, a stabilizer well in communication with said reservoir, a stabilizer plate in said well connected to said air valve to move in unison therewith, and an auxiliary fuel nozzle `connecting thetop of said well to said mixing chamber and surrounding the connection between the air valve and the stabilizer plate, whereby said well is filled by the suction in the carburetor. l

In testimonywhereof I have hereunto subscribed my name at Chicago, Cook County, Illinois.

CHESTER r. JoHNsoN.

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